I would stitch them to the fabric covering the inner ring, or if you have a drill, you could drill a very small hole in the hoop and thread the metallic thread through the hole from the back and pierce the fabric and thread through and the do the opposite on the other side using a knot to anchor the thread on the inside of the hoop.
Or when you are still assembling you could add a hanging loop either in metallic or ribbon to the inside of the hoop, you could attach this one with a ting blob of superglue (I'm with you about keeping glue away from stitching in most circumstances, if you are careful here though I think it would be fine) or you could anchor the hanging loop with a knot at the end, then pull through. Then finish with the backing the way you explained in FoF. Before it would attach to a flat surface it would dangle at an angle (
Hope this helps.






